From your Shopify admin, go to Online Store > Themes.
Find the theme that you want to edit and click Customize.
From the top-bar drop-down menu, select Cart.
Click the Cart page.
Enable cart notes: show/hide the note form.
Cart hold timer:
Enable: turn on/off this feature.
Hour: adjust the hour of the expiration time.
Minute: adjust the minute of the expiration time.